The present invention relates to power module design and, more particularly, to a pressure assembled power module capable of driving a motor controller or the like.
Conventional power module designs require that interconnections be made between a plurality of semiconductor devices mounted within the module. Due to the high currents encountered in such devices, the interconnections are typically made using relatively wide interconnect tracks, for example, patternable conductive runs on an insulated metal substrate (IMS). Other methods of interconnection include heavy weight wire bonds or the like.
Conventional power module designs which interconnect semiconductor devices using interconnect tracks or wire bonds are disadvantageous in that they require the semiconductor devices to be spaced apart and disposed in a generally coplanar orientation such that interconnections may be readily made. Consequently, such power modules are relatively large.
Conventional power module designs also are disadvantageous in that (1) they require that the semiconductor devices be mounted to a substrate by way of solder, ultrasonic bonding, or the like and (2) they require that the interconnect tracks or wire bonds be soldered or ultrasonically bonded to the semiconductor devices themselves. Consequently, stresses develop at the device-substrate and device-interconnect interfaces due to thermal mismatches therebetween.
Still further, the use of interconnect tracks or wire bonds for making interconnections between semiconductor devices within a power module introduces parasitic resistances and inductances into the circuit which increase heat dissipation and degrade electrical performance of the circuit (for example, reducing switching speeds).